We have recently developed an alternative theory of DNA renaturation kinetics. With the aid of this theory, we have discovered that many literature experiments were not performed under nucleation - rate-limiting conditions. Thus, we wish to re-examine experimentally the effect of strand length on the kinetics. Also, with our theory as a base, we wish to construct a theory for RNA - DNA hybridization and examine experimentally various aspects of these hybridizations. There is also a need for methods of fractionating and determining molecular weight of chromosomal DNA. We plan to extend our work on viscoelasticity and to develop a flotation method (the opposite of sedimentation) to fractionate huge chromosomal DNA.